Switching to the single-tablet regimen of elvitegravir, cobicistat, emtricitabine, and tenofovir DF from non-nucleoside reverse transcriptase inhibitor plus coformulated emtricitabine and tenofovir DF regimens: Week 96 results of STRATEGY-NNRTI.

BACKGROUND: HIV-1-infected, virologically suppressed adults wanting to simplify or change their non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens may benefit from switching to the single-tablet regimen of elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (E/C/F/TDF). OBJECTIVE: We examined differences in the proportion of participants with HIV-1 RNA < 50 copies/mL (Snapshot analysis), change in CD4 cell count, safety, and patient-reported outcomes in participants switching to E/C/F/TDF from an NNRTI + FTC/TDF (TVD) regimen. METHODS: STRATEGY-NNRTI was a 96-week, phase 3b, randomized, open-label, study examining the efficacy, safety, and tolerability of switching to E/C/F/TDF in virologically suppressed individuals (HIV-1 RNA < 50 copies/mL) on an NNRTI + TVD regimen. Participants were randomized to switch or remain on their NNRTI-based regimen (no-switch). RESULTS: At Week 96, 87% (251/290) of switch and 80% (115/143) of no-switch participants maintained HIV-1 RNA < 50 copies/mL (difference 6.1%; 95% CI -1.3 to 14.2%; p = 0.12) according to the FDA-defined snapshot algorithm. Both groups had similar proportions of subjects with virologic failure (2.8% switch, 1.4% no-switch). Discontinuations resulting from adverse events were infrequent (3% [9/291] switch, 2% [3/143] no-switch). Three switch participants (1%) discontinued due to renal adverse events (2 of the 3 before Week 48). Switch participants reported significant improvements in neuropsychiatric symptoms by as early as Week 4, and which were maintained through Week 96. CONCLUSIONS: E/C/F/TDF is safe and effective and reduces NNRTI-associated neuropsychiatric symptoms for virologically suppressed HIV-positive adults switching from an NNRTI plus FTC/TDF-based regimen.

Simplification to single-tablet regimen of elvitegravir, cobicistat, emtricitabine, tenofovir DF from multi-tablet ritonavir-boosted protease inhibitor plus coformulated emtricitabine and tenofovir DF regimens: week 96 results of STRATEGY-PI.

BACKGROUND: Antiretroviral therapy (ART) simplification to a single-tablet regimen can benefit HIV-1-infected, virologically suppressed, individuals on ART composed of multiple pills. OBJECTIVE: We assessed long-term efficacy and safety of switching to co-formulated elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (E/C/F/TDF) from multi-tablet ritonavir-boosted protease inhibitor (PI + RTV) plus F/TDF (TVD) regimens. METHODS: STRATEGY-PI was a 96-week, phase 3b, randomized (2:1), open-label, non-inferiority study examining the efficacy, safety, and tolerability of switching to E/C/F/TDF from PI + RTV + TVD regimens in virologically suppressed individuals (HIV-1 RNA <50 copies/mL). Participants were randomized to switch to E/C/F/TDF (switch group) or to continue their PI + RTV + TVD regimens (no-switch group). Eligibility criteria included no resistance to F/TDF or history of virologic failure, and estimated creatinine clearance ≥70 mL/min. RESULTS: At week 96, 87% (252/290) of switch and 70% (97/139) of no-switch participants maintained HIV-1 RNA <50 copies/mL (difference: 17%, 95% CI 8.7-26.0%, p < 0.001). Superiority of the switch to E/C/F/TDF vs. no-switch was due to a smaller proportion of both virologic failures (switch, 1% [3/290]; no-switch, 6% [8/139]) and discontinuations for non-virologic reasons (switch, 11% [31/290]; no-switch, 24% [33/139]). No treatment-emergent resistance was observed in switch subjects with virologic failure. Discontinuation rates from adverse events were 3% in both groups (9/293, switch; 4/140, no-switch). Switching from PI + RTV + TVD to E/C/F/TDF was associated with significant improvements in patient-reported outcomes related to gastrointestinal symptoms (nausea and bloating). CONCLUSION: E/C/F/TDF is a safe, effective long-term alternative to multi-tablet PI + RTV + TVD-based regimens in virologically suppressed, HIV-1-infected adults, and improves patient-reported gastrointestinal symptoms.

Atazanavir Plus Cobicistat: Week 48 and Week 144 Subgroup Analyses of a Phase 3, Randomized, Double-Blind, Active-Controlled Trial.

OBJECTIVES: Cobicistat (COBI) enhances atazanavir (ATV) pharmacokinetic parameters similarly to ritonavir (RTV) in both healthy volunteers and HIV-infected adults. Primary efficacy and safety outcomes of this Phase 3, international, randomized, double-blind, double-dummy, active- controlled trial in HIV-1-infected treatment-naïve adults (GS-US-216-0114/NCT01108510) demonstrated that ATV+COBI was non-inferior to ATV+RTV, each in combination with emtricitabine/ tenofovir disoproxil fumarate (FTC/TDF), at Weeks 48 and 144, with high rates of virologic success for both regimens (85.2% and 87.4%, respectively, at Week 48; and 72.1% and 74.1% at Week 144), and with comparable safety and tolerability. Here, we describe virologic response and treatment discontinuation by a wider range of subgroups than previously presented. METHODS: Subgroup analyses by baseline CD4 count (≤200, 201-350, >350 cells/mm3), baseline HIV-1 RNA level (≤100,000, >100,000 copies/mL), race, sex, and age (<40, ≥40 years) evaluated ATV+COBI versus ATV+RTV univariate odds ratios (ORs) for virologic success (viral load <50 copies/mL, intention-to-treat US Food and Drug Administration Snapshot algorithm) and discontinuation due to adverse events (AEs) at Weeks 48 and 144. Of 692 patients randomized, 344 received ATV+COBI and 348 ATV+RTV. RESULTS: ATV+COBI versus ATV+RTV ORs for virologic success did not significantly differ by regimen overall at Weeks 48 and 144 (OR 0.90; 95% confidence interval [CI]: 0.64, 1.26) or within subgroups, except in females, for whom ATV+COBI was favored at Week 144 (OR 2.36; 95% CI: 1.02, 5.47). However, there were more discontinuations due to withdrawal of consent and pregnancies in females receiving ATV+RTV versus ATV+COBI. ORs for discontinuation due to AEs did not significantly differ by regimen overall at Weeks 48 and 144 (OR 0.98; 95% CI: 0.61, 1.58) or within subgroups. CONCLUSION: These findings indicate that both ATV+COBI and ATV+RTV, each with FTC/TDF, are effective and well-tolerated treatment options across a wide demographic range of HIV-infected patients.

Integrase inhibitor versus protease inhibitor based regimen for HIV-1 infected women (WAVES): a randomised, controlled, double-blind, phase 3 study.

BACKGROUND: Women are under-represented in HIV antiretroviral therapy (ART) studies. Guidelines for selection of ART as initial therapy in patients with HIV-1 infection do not contain sex-specific treatment. We aimed to assess the safety and efficacy of the single tablet integrase inhibitor regimen containing elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate compared with a boosted protease inhibitor regimen of ritonavir-boosted atazanavir with emtricitabine and tenofovir disoproxil fumarate. METHODS: In this international, randomised, controlled, double-blind, phase 3 study (Women AntiretroViral Efficacy and Safety study [WAVES]), we recruited treatment-naive HIV-infected women with an estimated creatinine clearance of 70 mL/min or higher from 80 centres in 11 countries. Women were randomly assigned (1:1) to receive elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (integrase inhibitor regimen) or ritonavir-boosted atazanavir with emtricitabine and tenofovir disoproxil fumarate (protease inhibitor based regimen); regimens were masked with matching placebos. Randomisation was done by a computer-generated allocation sequence (block size four) and was stratified by HIV-1 RNA viral load and race. Investigators, patients, study staff, and those assessing outcomes were masked to treatment group. All participants who received one dose of study drug were included in the primary efficacy and safety analyses. The main outcome was the proportion of patients with plasma HIV-1 RNA less than 50 copies per mL at week 48 as defined by US Food and Drug Administration snapshot algorithm (prespecified non-inferiority margin of 12%). This study is registered with ClinicalTrials.gov, number NCT01705574. FINDINGS: Between Nov 28, 2012, and March 12, 2014, 575 women were enrolled. 289 were randomly assigned to receive the integrase inhibitor regimen and 286 to receive the protease inhibitor based regimen. 252 (87%) women in the integrase inhibitor group had plasma HIV-1 RNA less than 50 copies per mL at week 48 compared with 231 (81%) women in the protease inhibitor group (adjusted difference 6·5%; 95% CI 0·4-12·6). No participant had virological failure with resistance in the integrase inhibitor group compared with three participants ([1%]; all Met184Val/Ile) in the protease inhibitor group. 19 women in the protease inhibitor group discontinued because of adverse events compared with five in the integrase inhibitor group. INTERPRETATION: WAVES shows that clinical trials of ART regimens in global and diverse populations of treatment-naive women are possible. The findings support guidelines recommending integrase inhibitor based regimens in first-line antiretroviral therapy. FUNDING: Gilead Sciences.

Drug Interactions with Cobicistat- or Ritonavir-Boosted Elvitegravir.

Cobicistat and ritonavir are structurally distinct compounds that both potently inhibit cytochrome P450 (CYP) 3A, the metabolizing enzyme primarily responsible for the elimination of several antiretroviral medications, and, as such, are pharmacokinetic boosters for antiretroviral agents that require longer dosing intervals. Recently, cobicistat was approved for the treatment of HIV-1 infection in treatment-naive adults as a component of a single-tablet regimen consisting of cobicistat-boosted elvitegravir plus emtricitabine and tenofovir disoproxil fumarate. While studies have demonstrated that boosting with either cobicistat or ritonavir results in comparable plasma exposure of the target antiretroviral agent, a better understanding of drug-drug interactions between cobicistat- and ritonavir-boosted antiretrovirals and other medications will inform treatment decisions in HIV-infected patients. In connection with their distinct structural properties, COBI and RTV differ with respect to their drug-drug interaction profiles. Compared with ritonavir, cobicistat lacks induction potential and is a more specific inhibitor of 3A and therefore, has reduced effects on other CYP isoforms. To date, more studies have assessed ritonavir drug-drug interactions with other medications than have assessed cobicistat drug-drug interactions. The objective of this article is to review the drug-drug interactions when cobicistat- or ritonavir-boosted elvitegravir, cobicistat, or elvitegravir/cobicistat/emtricitabine/tenofovir are coadministered with antiretroviral therapies or drugs that are either substrates, inducers, or inhibitors of the CYP3A metabolic pathway, as well as with drugs that alter intra-gastric pH or are substrates of P-gp, in order to inform the proper use of elvitegravir/cobicistat/emtricitabine/tenofovir.

Pharmacokinetics of Co-Formulated Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Disoproxil Fumarate After Switch From Efavirenz/Emtricitabine/Tenofovir Disoproxil Fumarate in Healthy Subjects.

BACKGROUND: Elvitegravir (EVG), a HIV integrase inhibitor, is metabolized primarily by CYP3A, and secondarily by UGT1A1/3; Efavirenz (EFV), a HIV non-nucleoside reverse transcriptase inhibitor, is metabolized by Cytochrome P450 (CYP) 2B6 and induces CYP3A and uridine diphosphate glucuronosyltransferase (UGT) with residual effects post discontinuation because of long T1/2 (40-55 hours). This study evaluated the pharmacokinetics after switching from efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF) to elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF). METHODS: Healthy subjects (n = 32 including n = 8 CYP2B6 poor metabolizers) received EVG/COBI/FTC/TDF (150/150/200/300 mg) on days 1-7, and after a washout, received EFV/FTC/TDF (600/200/300 mg) on days 15-28 and switched to EVG/COBI/FTC/TDF (150/150/200/300 mg) for 5 weeks (days 29-62). Pharmacokinetic assessments occurred on days 7, 28, 35, and 42; trough samples (Ctrough) were collected periodically until day 63. Safety was assessed throughout the study. RESULTS: Twenty-nine subjects completed with 3 adverse events leading to discontinuation; no grade ≥3 adverse events were reported. Post-EFV/FTC/TDF, mean EVG area under concentration (AUCtau) was 37% and 29% lower and mean Ctrough ∼3- and ∼5-fold above IC95, respectively, on days 35 and 42, and 7-8-fold above IC95 by 5 weeks. COBI AUCtau returned to normal by day 42. EVG glucuronide, GS-9200, AUCtau was higher (46% and 32% on days 35 and 42, respectively) postswitch. CYP2B6 poor metabolizers displayed higher EFV AUCtau and Cmax (125% and 91%, respectively) versus non-poor metabolizers, and lower EVG and COBI exposures. EFV Ctrough was >IC90 (10 ng/mL) in all subjects postswitch. FTC and tenofovir (TFV) exposures were unaffected. CONCLUSIONS: After EFV/FTC/TDF to EVG/COBI/FTC/TDF switch, EVG and/or EFV exposures were in an active range. These findings support further evaluation of switching regimens in HIV-1 patients.

Concordance of HIV-1 RNA Values by Amplicor and TaqMan 2.0 in Patients With Confirmed Suppression in Clinical Trials.

BACKGROUND: The COBAS AMPLICOR HIV-1 MONITOR Test, version 1.5 (Amplicor) has been replaced with the COBAS AmpliPrep/COBAS TaqMan HIV-1 Test, version 2.0 (TaqMan 2.0), a real-time polymerase chain reaction human immunodeficiency virus type 1 (HIV-1) assay with higher sensitivity and broader dynamic range. HIV-1 RNA values at the 50 copies/mL cutoff drive major patient management decisions and clinical study outcomes. METHODS: A total of 2217 samples were collected from 1922 HIV-1-infected subjects taking antiretroviral therapy for at least 48 weeks and had at least 2 consecutive samples with HIV-1 RNA <50 copies/mL by Amplicor from 7 recent clinical trials. HIV-1 RNA results were obtained from the Amplicor and TaqMan 2.0 assays in parallel by a reference laboratory. RESULTS: The overall concordance between assay results was 96% at the cutoff of 50 copies/mL. However, statistically significant discordance at the 50 copies/mL cutoff was found between the assays for 3.9% of samples (n = 87). By TaqMan 2.0, virologic failure defined as HIV-1 RNA ≥ 50 copies/mL was reported for 2.8% more samples than Amplicor. Of these 87 samples, 68 samples fell within the predicted range of assay variability. Retesting of HIV-1 RNA by TaqMan 2.0 confirmed the discordance in only 28 of the 87 samples. CONCLUSIONS: The TaqMan 2.0 assay reports fewer subjects below the clinical endpoint of HIV-1 RNA <50 copies/mL in HIV clinical trials than the Amplicor assay. This difference must be considered when assessing disease progression, designing clinical trials, and comparisons with historical trials that used the Amplicor assay.

Pulmonary hypertension in idiopathic pulmonary fibrosis with mild-to-moderate restriction.

The clinical course of pulmonary hypertension (PH) in idiopathic pulmonary fibrosis (IPF) is not known except in advanced disease.488 subjects in a placebo-controlled study of ambrisentan in IPF with mild-moderate restriction in lung volume, underwent right heart catheterisation (RHC) at baseline and 117 subjects (24%) had repeated haemodynamic measurements at 48 weeks. The subjects were categorised into a) World Health Organization (WHO) Group 3 PH (PH associated with pulmonary disease), n=68 (14%); b) WHO Group 2 PH (PH associated with left-sided cardiac disease), n=25 (5%); c) no PH but elevated pulmonary artery wedge pressure (PAWP), n=21 (4%); and d) no PH but without elevation of PAWP, n=374 (77%). The WHO Group 3 PH subjects had a lower diffusion capacity, 6MWD and oxygen saturation compared to the subjects with no PH. There was no significant change in mean pulmonary arterial pressure with ambrisenten or placebo after 12 months. Subjects with IPF associated with WHO Group 3 PH had impaired gas exchange and exercise capacity compared to patients without PH. An additional 9% of the subjects had haemodynamic evidence of subclinical left-ventricular dysfunction. Pulmonary artery pressures remained stable over 1 year in the majority of the cohort.

Brief Report: Cobicistat Compared With Ritonavir as a Pharmacoenhancer for Atazanavir in Combination With Emtricitabine/Tenofovir Disoproxil Fumarate: Week 144 Results.

BACKGROUND: Cobicistat (COBI) is a pharmacoenhancer with no antiretroviral activity. METHODS: International, randomized double-blind active-controlled trial to evaluate the efficacy and safety of COBI vs ritonavir (RTV) as a pharmacoenhancer of atazanavir in combination with emtricitabine/tenofovir disoproxil fumarate in HIV treatment-naive patients followed through week 144. RESULTS: At Week 144, virologic suppression was achieved in 72% (COBI) and 74% (RTV) of patients. Adverse events leading to study drug discontinuation occurred in 11% of patients in each group. Median changes in serum creatinine (mg/dL) were +0.13 (COBI) and +0.07 (RTV) and were unchanged from week 48. CONCLUSIONS: Once-daily COBI is a safe and effective pharmacoenhancer of the protease inhibitor atazanavir.

Differential Reduction in Monocyte Activation and Vascular Inflammation With Integrase Inhibitor-Based Initial Antiretroviral Therapy Among HIV-Infected Individuals.

BACKGROUND: Little is known about how different antiretrovirals effect inflammation and monocyte activation in human immunodeficiency virus (HIV) infection. METHODS: We examined plasma specimens obtained during a randomized, double-blinded trial in antiretroviral therapy (ART)-naive HIV-infected adults which compared the efficacy of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/c/FTC/TDF) with that of efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF). From a random sample achieving an HIV type 1 RNA load of <50 copies/mL by week 48, changes over 24 and 48 weeks in levels of biomarkers of monocyte activation (soluble CD14 [sCD14] and soluble CD163 [sCD163]), systemic inflammation (soluble tumor necrosis factor α receptor I [sTNF-RI], interleukin 6 [IL-6], and high-sensitivity C-reactive protein [hsCRP]), and vascular inflammation (lipoprotein-associated phospholipase A2 [Lp-PLA2]) were compared. Multivariable linear regression was used. RESULTS: A total of 200 participants were included. Significant differences favoring EVG/c/FTC/TDF were noted for changes in sCD14, hsCRP, and Lp-PLA2 levels. Factors independently associated with a larger decrease in the sCD14 level included random assignment to receive EVG/c/FTC/TDF, higher baseline sCD14 level, and larger decreases in hsCRP and sCD163 levels; factors associated with a larger Lp-PLA2 decrease included higher baseline Lp-PLA2 and IL-6 levels, smaller increases in total cholesterol and triglycerides levels, a larger decrease in the sCD14 level, and a smaller decrease in the sCD163 level. CONCLUSIONS: EVG/c/FTC/TDF led to greater decreases in sCD14, hsCRP, and Lp-PLA2 levels, compared with EFV/FTC/TDF. Randomization group independently predicted the change in sCD14 level, and changes in monocyte activation independently predicted the change in Lp-PLA2 level. There appears to be a more favorable effect of the integrase inhibitor EVG over efavirenz on immune activation, which may affect vascular inflammation.

Elvitegravir/cobicistat/emtricitabine/tenofovir DF in HIV-infected patients with mild-to-moderate renal impairment.

In HIV-1-infected treatment-naive patients with mild-to-moderate renal impairment [creatinine clearance (CrCl): 50-89 mL/min], elvitegravir/cobicistat/emtricitabine/tenofovir DF (STB, n = 33) achieved high rates of virologic success (78.8%; 95% confidence interval: 61.1% to 91.0%) and was well tolerated through week 48. Four patients discontinued study drug due to an adverse event and none due to proximal renal tubulopathy. As expected, decreases in CrCl were noted as early as week 2, after which they stabilized. The renal safety profile of STB in patients from this study is consistent with the long-term experience in a large number of patients with CrCl ≥70 mL/min.

Week 144 resistance analysis of elvitegravir/cobicistat/emtricitabine/tenofovir DF versus efavirenz/emtricitabine/tenofovir DF in antiretroviral-naive patients.

BACKGROUND: Here, the baseline and emergent resistance to elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF) versus efavirenz (EFV)/FTC/TDF in HIV-1-infected antiretroviral-naive adults through 144 weeks from the randomized, ongoing, Phase III study GS-US-236-0102 is described. METHODS: HIV-1 protease (PR) and reverse transcriptase (RT) were sequenced at screening; patients with HIV-1 resistant to EFV, FTC or TDF were excluded. Genotypic/phenotypic analyses were performed at virological failure confirmation and baseline for PR, RT and integrase (IN) for patients with virological failure and for patients with HIV-1 RNA≥400 copies/ml at weeks 48, 96, 144 or early study drug discontinuation. Retrospective, baseline, IN genotyping was conducted for EVG/COBI/FTC/TDF patients. RESULTS: In the EVG/COBI/FTC/TDF group through week 144, HIV-1 from 10 patients (2.9%; 10/348 treated patients) developed primary IN strand transfer inhibitor (n=9) and/or nucleoside RT inhibitor resistance substitutions (n=10). The emergence of resistance decreased over time with 8, 2 and 0 patients developing HIV-1 resistance through week 48, post-week 48-96 and post-week 96-144, respectively. Emergent substitutions were E92Q (n=7), N155H (n=3), Q148R (n=1) and T66I (n=1) in IN, and M184V/I (n=10) and K65R (n=4) in RT. All 10 isolates had reduced susceptibility to EVG, FTC or TDF. Virus with EVG phenotypic resistance had cross-resistance to raltegravir. In the EFV/FTC/TDF group, virus from 14 patients (4.0%; 14/352 treated patients; 4 during weeks 96-144) developed a resistance substitution to EFV (n=14; K103N: n=13), FTC (M184V/I: n=4) or TDF (K65R: n=3). CONCLUSIONS: Resistance development to EVG/COBI/FTC/TDF was infrequent through 144 weeks of therapy and decreased over time, consistent with durable efficacy.

Cobicistat-boosted protease inhibitors in HIV-infected patients with mild to moderate renal impairment.

BACKGROUND: Cobicistat (COBI) is a pharmacoenhancer that optimizes systemic exposures of protease inhibitors (PIs) such as atazanavir (ATV) and darunavir (DRV). OBJECTIVE: To evaluate the efficacy and safety of switching ritonavir (RTV) to COBI in patients with creatinine clearance (CrCl) 50 to 89 mL/min who are virologically suppressed on a stable regimen containing ritonavir (RTV)-boosted ATV or DRV. Other components of the regimen remained unchanged. METHODS: A phase 3, non-comparative, open-label clinical trial. RESULTS: Seventy-three patients were enrolled. At week 48, 82% maintained virologic suppression. No emergent resistance developed. Serious adverse events (AEs) occurred in 7%, and study drug discontinuation due to AEs occurred in 10% (7 patients). There were 2 renal discontinuations and no cases of proximal renal tubulopathy. Small reductions in CrCl (median [IQR]) were observed as early as week 2, after which they were nonprogressive through week 48 (-3.8 [-9 to 0.8]). Changes in CrCl by baseline CrCl (< 70 vs ≥ 70) were -1.1 [-6.5 to 6.3] versus -6.6 [-12.4 to -0.7], respectively. CONCLUSIONS: In HIV-1-infected patients with CrCl 50 to 89 mL/min switching from RTV to COBI, COBI-boosted PIs in combination with 2 nucleos(t)ide reverse transcriptase inhibitors were well-tolerated and effective in maintaining virologic suppression. The renal safety profile of COBI in this study was consistent with the long-term data in patients without renal impairment from the phase 3 studies of COBI-containing regimens.

Long-term efficacy and safety of E/C/F/TDF vs EFV/FTC/TDF and ATV+RTV+FTC/TDF in HIV-1-infected treatment-naïve subjects ≥50 years.

INTRODUCTION: In high-income countries, ≥30% of HIV-infected patients are ≥50 years (yrs) old (UNAIDS 2013). In two phases, three clinical trials (Studies 102 and 103) elvitegravir/cobicistat/emtricitabine/tenofovir DF (E/C/F/TDF; STB) had non-inferior efficacy and favourable safety vs efavirenz/emtricitabine/tenofovir DF (EFV/FTC/TDF; ATR) or ritonavir-boosted atazanavir (ATV+RTV)+FTC/TDF (TVD) in HIV-infected, treatment-naïve subjects at Week 144. The efficacy and safety of STB in subjects < or ≥50 yrs is described. MATERIALS AND METHODS: Post hoc analysis of efficacy, tolerability and safety in subjects < or ≥50 yrs at Week 144. RESULTS: Subjects ≥50 yrs in Study 102: STB: 14% (49/348), ATR: 16% (56/352); in Study 103: STB: 14% (48/353), ATV+RTV+TVD: 14% (48/355). Efficacy, safety and tolerability by age and study endpoint are shown in Table 1. Regardless of age, STB had robust efficacy at Week 144 with similar virologic outcomes vs ATR or ATV+RTV+TVD. Discontinuations (DC) due to AE on STB were similar to the comparators, most occurred by Week 48. Median changes in eGFR on STB were similar by age; DC with renal PRT was rare [STB: 4 (0.6%); ATV: 3 (0.8%); ATR: 0], 2 and 1 in ≥50 yrs old strata, respectively. CONCLUSIONS: STB compared to ATR or ATV+RTV+TVD, is an efficacious, well-tolerated and safe regimen for HIV-1-infected, treatment-naïve subjects

Phase IIIb, open-label single-arm trial of darunavir/cobicistat (DRV/COBI): Week 48 subgroup analysis of HIV-1-infected treatment-nave adults.

INTRODUCTION: COBI, a PK enhancer with no ARV activity is a more selective cytochrome P450 (CYP)3A inhibitor than ritonavir (RTV), does not induce CYP isozymes, and thus has less potential for drug-drug interactions. COBI boosts DRV PK as effectively as RTV in healthy volunteers. MATERIALS AND METHODS: This 48-week, phase IIIb, open-label, single-arm, US multicentre study (NCT01440569) included HIV-infected treatment-nave and experienced adults with no DRV RAMs, viral load (VL) ≥1000 c/mL, eGFR ≥80 mL/min and genotypic sensitivity to investigator-selected N[t]RTIs. Patients received DRV/COBI 800/150 mg qd (as single agents) plus two fully active N[t]RTIs. The primary endpoint was any treatment-emergent grade 3 or 4 AEs through Week 24. We report 48-week safety, efficacy and PK/PD results in treatment-nave patients. RESULTS: Of 313 ITT patients, 295 were treatment-nave (94%). In the treatment-nave cohort, 90% were male, 60% white and 294 (99.7%) received a TDF-containing regimen. Median baseline (BL) VL was 4.8 log10 c/mL and CD4(+) 370 cells/mm(3). Treatment-emergent grade 3 or 4 AEs regardless of causality were reported in 21 (7%) patients. AEs regardless of causality (any grade; ≥10% of patients) were: diarrhoea (27%), nausea (23%), URTI (15%) and headache (12%). Sixteen (5%) patients had AEs leading to study drug discontinuation, most frequently rash (three patients), hypersensitivity and nausea (two patients each). Consistent with the known inhibition of tubular creatinine secretion by COBI, there was a mean increase from BL in serum creatinine by week 2 (0.09 mg/dL), remaining stable through week 48 (mean 0.10 mg/dL increase from BL). At week 48, 83% of patients achieved VL<50 c/mL; FDA Snapshot); median increase in CD4(+) was 169 cells/mm(3). Eight patients met the criteria for resistance testing. M184V was detected in one pt receiving FTC. New primary RAMs were not detected in the other seven patients. The mean population PK-derived DRV AUC24h was 100,620 ng.h/mL and C0h 2,105 ng/mL (n=281). There were no clinically relevant relationships between DRV exposure and virologic response, AEs or laboratory parameters. CONCLUSIONS: The DRV PK of DRV/COBI was consistent with historical data for DRV/RTV. DRV/COBI 800/150 mg qd plus two N(t)RTIs had an 83% response and was well tolerated through Week 48. These results are similar to published data for DRV/RTV 800/100 mg qd, and support the use of DRV/COBI 800/150 mg qd in treatment-nave patients.

Switching from ritonavir to cobicistat in HIV patients with renal impairment who are virologically suppressed on a protease inhibitor.

INTRODUCTION: Cobicistat (COBI) is a pharmacoenhancer and one of the components of ECF/TDF (elvitegravir/cobicistat/emtricitabine/tenofovir DF), which is approved in treatment-naïve HIV patients with creatinine clearance (CrCl) ≥70 mL/min. Study 118 assessed the renal safety of COBI-containing regimens in HIV patients with mild to moderate renal impairment. MATERIAL AND METHODS: Phase 3, open label study in HIV-1-infected patients with CrCl 50-89 mL/min who are virologically suppressed on a stable regimen containing ritonavir (RTV)-boosted atazanavir (ATV) or darunavir (DRV). Patients switched RTV to COBI, while keeping the rest of their regimen unchanged. We present the 96-week (Wk) data. RESULTS: Seventy-three patients were enrolled. Mean age was 54 years; male 82%; white 77%; hypertension 38%; diabetes 18%; baseline proteinuria (≥trace) 51%; median CrCl 71 mL/min (range: 42-98). At Wk 96, 89% maintained virologic suppression (95% CI 77.4-95.8%). No emergent resistance developed. Reductions in CrCl (median [IQR]) were observed as early as Wk 2, after which they were nonprogressive through Wk 96 (Wk 48: -3.8 [-9-0.8]; Wk 96: -5.0 [-13.0-0.1]). Changes in CrCl by baseline CrCl (<70 vs ≥70) at Wk 96 were: -3.1 [-5.1-0.5] vs -7.6 [-15.2 to -3.6], respectively. Cystatin C-based eGFR remained stable through Wk 96 (median [IQR]: -2.8 [-7.4-8.9 mL/min/1.73 m(2)). Actual GFR assessment using CLiohexol (n=14) was unaffected over 24 Wks (median at baseline: 82.5, median changes from baseline at Wks 2, 4, and 24: 1.6, 7.0, -4.1 mL/min, respectively). Three renal discontinuations occurred (two worsening CrCl and one proteinuria/hematuria); none had proximal renal tubulopathy [PRT]. No patient had laboratory evidence of PRT (>1 confirmed renal laboratory abnormalities [increase in serum Cr≥0.4 mg/dL, ≥2-grade increase in proteinuria,≥1-grade increase in normoglycemic glycosuria or hypophosphatemia]). CONCLUSIONS: In HIV-infected patients with CrCl 50-89 mL/min, on ATV- or DRV-based regimen switching to COBI from RTV, demonstrated that COBI was well tolerated with no cases of PRT through 96 Wks. The renal safety profile of COBI in patients with mild to moderate renal impairment was consistent with the long-term data in patients without renal impairment (CrCl≥70 mL/min) from the phase 3 studies of COBI-containing regimens.

Week 144 resistance analysis of elvitegravir/cobicistat/emtricitabine/tenofovir DF versus atazanavir+ritonavir+emtricitabine/tenofovir DF in antiretroviral-naïve patients.

OBJECTIVE: To describe baseline and emergent HIV-1 resistance to elvitegravir/ cobicistat/emtricitabine/tenofovir DF (EVG/COBI/FTC/TDF) and ritonavir-boosted atazanavir/emtricitabine/tenofovir DF (ATV+RTV+FTC/TDF) in HIV-1-infected, treatment-naïve subjects through 144 weeks. METHOD: This was a randomized, double-blind, phase 3 study. HIV-1 protease (PR) and reverse transcriptase (RT) were sequenced at screening. Genotypic and phenotypic analyses were performed at virologic failure confirmation and retrospectively at baseline for PR, RT, and integrase (IN) for patients with virologic failure through week 144. RESULTS: In the EVG/ COBI/FTC/TDF group through week 144, HIV-1 from 8 patients (2.3%; 8/353 treated patients) developed primary IN strand transfer inhibitor (INSTI) (n = 6) and/or nucleoside RT inhibitor (NRTI) resistance substitutions (n = 7). The emergence of resistance decreased after the first year, with 5 patients developing HIV-1 resistance through week 48, 1 from weeks 48-96, and 2 from weeks 96-144. Emergent substitutions were E92Q, N155H, or Q148R (n = 2 each) and T66I or T97A (n = 1 each) in IN and M184V/I (n = 7) and K65R (n = 1) in RT. All 8 isolates had reduced susceptibility to EVG, FTC, or TDF. Virus with EVG phenotypic resistance showed cross-resistance to raltegravir. In the ATV+RTV+FTC/TDF group, HIV-1 from 2 patients (0.6%; 2/355 treated patients; both at week 144) developed the resistance substitution M184V/I in RT. CONCLUSIONS: Resistance development to EVG/COBI/FTC/TDF was infrequent (2.3%) through 144 weeks of therapy and decreased over time, consistent with durable efficacy.

Cobicistat-boosted darunavir in HIV-1-infected adults: week 48 results of a Phase IIIb, open-label single-arm trial.

BACKGROUND: Cobicistat is an alternative pharmacoenhancer to ritonavir. In healthy volunteers, darunavir exposure was comparable when darunavir 800 mg once daily was co-administered with cobicistat 150 mg once daily (as single agents or a fixed-dose combination) vs. with ritonavir 100 mg once daily. METHODS: This 48-week, Phase IIIb, single-arm, US multicenter study (NCT01440569) evaluated safety, efficacy and pharmacokinetics of darunavir/cobicistat 800/150 mg once daily (as single agents) plus two investigator-selected nucleoside/tide reverse transcriptase inhibitors (N[t]RTIs) in HIV-1-infected adults. Patients had no darunavir resistance-associated mutations (RAMs), plasma viral load (VL) ≥1000 HIV-1 RNA copies/ml, eGFR ≥80 ml/min and genotypic sensitivity to the two N[t]RTIs. The primary endpoint was any treatment-emergent grade 3 or 4 adverse events (AEs) through Week 24. RESULTS: The majority of the 313 intent-to-treat patients were treatment-naïve (295/313; 94%), male (89%), White (60%) and received a tenofovir-based regimen (99%). Median baseline VL and CD4(+) count overall were 4.8 log10 HIV-1 RNA copies/ml and 361 cells/mm(3), respectively. Overall, 86% of patients (268/313) completed the study. The majority of discontinuations were for AEs (15/313; 5%). The incidence of treatment-emergent grade 3 or 4 AEs regardless of causality was 6% through Week 24 and 8% through Week 48. Most common AEs through Week 48 were diarrhea (27%) and nausea (23%), which were grade 1 or 2 in severity. Week 48 virologic response rates (% with VL <50 HIV-1 RNA copies/ml; Snapshot analysis) were 81% overall and 83% in treatment-naïve patients; median increases in CD4(+) count at 48 weeks were 167 and 169 cells/mm(3), respectively. Of 15/313 patients who met the criteria for resistance analysis, one developed a darunavir RAM as a mixture with wild-type (I84I/V), without phenotypic resistance to darunavir. The mean population pharmacokinetic-derived darunavir areas under the plasma concentration-time curve were 102,000 overall and 100,620 ng•h/ml in treatment-naïve patients. No clinically relevant relationships were seen between darunavir exposure and virologic response, AEs or laboratory parameters. CONCLUSION: Darunavir/cobicistat 800/150 mg once daily was generally well tolerated through Week 48, with no new safety concerns. Pharmacokinetics, virologic and immunologic responses for darunavir/cobicistat were similar to previous data for darunavir/ritonavir 800/100 mg once daily.